The CORE Program is designed to encompass the cancer research activities of The Wistar Institute. The key objectives of the program concern: 1) modulation of the phenotypic expression of cellular antigens in normal and malignant cells; 2) components of the immune response and their interaction in the host-tumor response; 3) structure changes in cell surface membranes in normal and transformed cells; 4) virus-cell interaction in neoplastic transformation - determination of some regulatory events involved in this interaction; 5) the role of chemical carcinogens in oncogenesis; 6) regulatory elements associated with cell growth and the phenotypic expression of specific cell functions; 7) application of quantitative cytochemistry and cell cycle analysis to tumor biology; and 8) genetic analysis of regulatory aspects of oncogenesis. In pursuit of these objectives, a wide variety of biochemical, biophysical and biological methods will be employed. BIBLIOGRAPHIC REFERENCES: Kroprowski, H. and C.M. Croce. Tumorigenicity of simian virus 40 transformed human cells and mouse-human hybrids in nude mice. Proc. Natl. Acad. Sci. USA 74:1142-1146, 1977. Maul, G.G., Z. Steplewski, J. Weibel and H. Koprowski. Time sequence and morphological evaluations of cells fused by polyethylene glycol 6000. In Vitro 12:787-796, 1977.